Portable, wireless communication devices, such as pagers, mobile (cellular) telephones, Personal Digital Assistants (PDA's), etc., all have a requirement to consume as little power as possible since they are battery operated and it is desirable to extend the battery lifetime as far as possible before it requires replacement or recharging. Many such devices include a LCD having one portion which is used to display alphanumeric (or other) characters on a dot matrix display to provide changeable information to a user. Another portion of the LCD is used to display symbols, such as icons, which indicate the status of the device or other simple information to the user. The dot matrix display portion of the LCD generally requires relatively high voltage and consumes high power. The icon display portion requires relatively low voltage and consumes low power.
As more and more information is desired by users, more and more icons, or symbols are being displayed on the icon display portion, including, for example the date and/or time. However, to maintain low voltage use for the icon display portion would require an extra pin on the LCD driver chip for each extra icon, which is clearly undesirable, since it would increase chip size. Therefore, the icon display portion is generally connected as an extra line of display to the multiplexed lines of the dot matrix display portion. Thus, when the LCD is used to display information on the dot matrix display portion, as well as the icon display portion, the full (relatively high) voltage is required. When, however, only the icon display portion is required to be used, again the full voltage is necessary to power up the whole LCD, although the dot matrix display portion is kept clear of characters. Thus, even when the dot matrix display portion is not being utilized, it is still turned on and consumes power.